The process for producing coal gas using pulverized coal generally comprises: feeding pulverized coal, vapor, air and oxygen into a coal gas producer, for reaction under a high temperature to produce the coal gas; passing the produced coal gas through a cyclone dust collector while recovering and sending pulverized coal back into the coal gas producer; the coal gas being passed through a waste heat boiler for producing vapor, and sending scrubbed and cooled coal gas to users. Since the temperature of the coal gas coming out of the coal gas producer is very high, the vapor produced through the waste heat boiler is in excess of what is needed for producing the coal gas, and the excessive portion will be used for other applications. At the same time, since the temperature of gasification agent composed of vapor, air and oxygen entering into the coal gas producer is relatively low, usually 65° C.-120° C., while reacting in the coal gas producer, the temperature of the gasification agent needs to be increased to 1000° C.-1100° C., a large amount of reaction heat will be consumed during increasing the temperature of the gasification agent. All of the factors above lead to the coal consumption in producing unit coal gas being relatively high, usually above 0.3 kg/Nm3-0.4 kg/Nm3; and the thermal value of the coal gas produced using above traditional process is low.